Grinding device for lawn mowers



Jan. 13, 1953 o. c. RINK 2,624,983

GRINDING DEVICE FOR LAWN MOWERS Filed April 27, 1950 5 Sheets-Sheet 2 Oscar ,1D/hk Gttornegs Jan. 13, 1953 o. c. RINK 2,624,983

GRINDING DEVICE FOR` LAWN MOWERS Filed April 27, 1950 3 Sheets-$heet 3 .6: 9] 7g /3//38 i :'17 90 f mi i@ 27,2%

:inventor Gttorneg @atente Jan. 13, 1953 NITED STATES ENT OFFICE 4 Claims.

This invention relates to a grinding machine for the blades of lawn mowers, and more particularly to a grinding machine adapted to sharpen the blades oi' lawn and power mowers without removing the blades therefrom.

The principal object of the present invention is to provide a clamping member on the grinding machine for mounting the mower in its entirety thereon so that a grinding wheel of the machine may contact the blades and be moved thereacross without removing the blades from the mower.

Other objects of the invention are to provide a support including a platform upon which the clamping member is mounted and a rotatable frame on said support carrying the grinding wheel which is manually slidable across the rotatable frame when the grinding wheel is in contact with the blade; to provide for adjustable mounting of the grinding wheel with respect to the blades of the mower when the mower is held on the support by the clamping member; to provide a platform on the support so it may slide thereon to adjust the grinding wheel with respect to the blades on mowers of different size; to provide a second clamping member on the end of the platform opposite the first clamping member for mounting the stationary blade of the mower; to provide means on the frame for rotating the same on the platform for positioning the grinding member for sharpening the horizontal blade; to provide vmeans on the frame for adjusting the grinding wheel with respect to the blade being sharpened;

Ato provide a track on the frame for movement of the grinding wheel mechanism thereacross; to provide roller mounting of the motor on said track; to provide means on the frame for adjustment of the grinding wheel relatively to the blade by movement of the grinding wheel on an axis with the shaft on which the motor is mounted; to provide a device of this character easily knocked down and packed for shipment in a compact condition, and to provide a device of this character simple, economical to manufacture and eITicient in operation.

In accomplishing these and other objects of the invention, I have provided improved structure, the preferred forms of which are shown in the accompanying drawings, wherein:

Eig. 1 is a perspective view of a grinding machine embodying the features of the invention.

Fig. 2 is a vertical sectional view through a part of the machine showing the mower mounted on the clamping member and the grinding wheel in contact with a blade of the mower.

Fig. 3 is a top plan view of the machine with parts broken away to better illustrate the invention.

Fig. 4 is an elevational view partly in section particularly showing the motorand motor mounting frame.

Fig. 5 is a cross section through a part of the frame particularly illustrating the eccentric'arrangement for adjustment of the grinding member to the blade.

Fig. 6 is an elevational view partly in section showing the adjusting mechanism of the grinding wheel to the blade.

Referring more in detail to the drawings:

I designates a grinding machine embodying the features of the present invention and comprising a tubular standard 2 having a plurality of removable feet 3 clamped to the lower portion thereof by bolts 5 and provided with a cap plate 6 secured thereto, as by Welding, and forming a base or support for a platform 1. The platform 'l is preferably a casting having end portions 8 and V9 and sides Ill and II being connected by a central horizontal web I2. Plate 6 and web l2 are provided with aligning apertures through which bolts I3 are applied to secure the platform l to the standard 2. A pair of braces Il` and I5 are provided on each side of the standard and secured thereto by a bolt I6 the other ends of the braces being secured to the respective sides I9 and II of the platform near the ends 8 and 9 by bolts I'I and I8 to form a rigid structure.

A frame structure I9 is slidably and rotatably mounted on the platform 1. A plate 20 having depending flanges 2l and 22 near its respective ends is provided for movement across the top of the platform 'I. Guide rails 23 and 2A are welded to the inner side of the depending sides I6 and I l near the top thereof and a plate 25 having upstanding pins 2t is adapted to slide beneath the guide rails and longitudinally thereof. A plate 28 is welded to the plate 20 and a plate 29 is welded to the underneath side substantially near the center of a base member 30 of the frame I9. The base member 3Q, plates 29, 28 and 20 are centrally bored and the plate 25 is also centrally bored and threaded for receiving the threaded end 3l of a bolt 92 which holds the frame I9 to the platform i. By loosening the bolt 32 theframe may be moved longitudinally of the platform 'l as desired.

The base member 39 of the frame is an inverted channel and the flanges thereof are connected by a web 33 for stilfening the channel. Mounted on the respective ends of the base member are trunnions 34 for arms 35 and 36, the trunnions extending into openings in the respective ends of the arms, the arms being provided with slots 3l for a purpose later described. The arms 35 and Sii have enlarged lower ends as indicated at vrigidity `to the jarm structure. M 'tion-63 of the housing for the grinding wheel -is =provided with a threaded opening adapted thear'ms35 'and 36. 'tubularmember 16 jadjacent the arm 35 and has a threaded opening adapted to receive a set Ascrew 82 for holding the collar thereon. Secured to the collar opposite the setl screw by welding yor the like is'a rod-83 adapted to engage in an 3 38 and spaced from the openings for the trunnions are openings 39 into which the respective ends f a tube 40 are pressed and held rigidly to the -arms. `The tube 40 forms a trackway for mounting of a motor 4| and a grinding wheel 42 thereon also later described;

`The motor 4|e is provided with a base plate 43 `adapted to Vbe secured to a carriage plate 45 by bolts or the like 46. The plate 45 is provided with a depending base lug 41, the lug v41 being provided with spaced threaded openings that are angularly directed on the underneath side thereof to receive the threaded shanksnof stud bolts 48 and 49. Mounted on the stud bolts 48 and 49 are rollers 50 and 5| spaced so that they engage the respective upper sides of the tubular trackway 4I) for movement of the motor across the framework structure. Y

J Anarm l'2 projects from the motor carriage plate 45 for mounting of the grinding wheel 42 thereon.A The inner end of the arm 52 is provided 4witha slot `53 forminga fork for engaging over, the carriage plate as best illustrated in Fig. 6, and is secured thereto by bolts 53. The

ggutersend of the arm 52 is provided with a head 54 consisting ofl a housing 55 Vprovided with lopenings near the lower edge thereof adapted to receive ashaft 56 of grinding wheel 42. The

housing 55 removably mounted on the arm by cap screws 51'and 58','thev arm 52 being pro- "vided with a depending portion 59 having a bore Yopening, in which a cap screw 58 extends. The

extension 60 of the .armu'52 is -provided with openings adapted to receive vthe vcap screws 51 andf58f to hold the` upper end of the housing rigidly to the arm. Integrally formed with the arm59 landthe arm-52`is a brace 6I to lend The front-porto receive ja cap screw 64 for mounting of the eye shield 65 thereon. Y Y

The v'housing`55 has an extensionvon Vone Vside providing-'a housing-61 for a pulley 68 mounted vr n theshaft 56 and held thereon by the usual set screw (not'shownL, The motor 4I is provided 'withthai-usual'shaft 691upon which is mounted v`a pulley fand a belt 1| runs over the pulleys '6'81and10 for rotating the grinding Vwheel 42 'upgon operationy of the motor.

vTheouter ends ofthe arms35l and 36 are provided 4with openings V12 in which are rotatably mountedsh'ort shafts 13 having eccentric lon- 'gitudinal'bores 14 adapted to lreceive pins 15.

'A'tubular member16 extends between the outer 'endsof the arms 35 and 36 in alignment with "thepins '15. VMounted within the ends of the "tubular member `16-are couplers 11 threadedly bored` at feach Aend'and a rod 18 provided with The bores 'of the 'coupling members 11 and their outer ends are provided with nuts 19', as best illustrated in Fig.'5. Washers 88 are provided on 'the'pins'15'between the tubular member 15 and A collar 8| surrounds the opening 84 of a'pin-85 rigidly secured in an opening 86 in the arm 35 spaced from the end of the arm as best illustrated in Fig. 5, the rod 83 acting as a guide, as later will be described.

The tubular member 16 is provided with a threaded opening 81 near the center thereof adapted to receive a screw 88 to provide a bend or slight arc in the member 15 to adjust the grinding wheel to the reel of the mower upon which the blades are mounted which will later appear. Each of the short shafts 13 is laterally bored and provided with threads as indicated at 83 for receiving a threaded end of a rod 90 having head 9| for movement of the short shaft to provide for eccentric adjustment of the rod.

Mounted on the respective ends 8 and 9 of the platform near the lower portion thereof are clamping devices 92 and 93. As these clamping devices are substantially identical, only one will be described. A plate 94 is secured to the end 9 of the platform by bolts 95 and 96 and formed integral with the plate member are outwardly extending base arms 91 and 98 having notches'99 and |00 in their upwardedges forming lower jaws. Extending upwardly near the plate 94 on each arm are ears I0| to which arepivotally mounted by bolts or the like |02, jaws |03 and |04 extendingvertically above"the'lower jaws 91 and 98. The lowerja'wsv are'provided with an opening near the outer end for 'pivotally mounting, by Vmeans cf bolts |05, Jclevis'es`lll6 vand'||)1. The outer end ofthe clevises arefthre'adedlybo'red and provided with set screws '|08 and L|09 respectively.

||`0 designates `the 'axleof Va mower having vwheels I |I carrying'afframe A| |2 upon which is mounted-a 'reel 'I I'3`h`aving a plurality of spiral blades |4. The frame also carries a stationary Iblade ||5 running parallel with the axis of the reel and secured' to a stiffening bracket I5' which is the usual practice andthe blade I I 5 is provided with a sharp edge as indicated' at I I6. I I1 designates a roller at'the rear ofthe mower is also the usual practice. I

When mounting'themo'wer on the clamping vdevice 92 the axle AII'Il'is placed in the notches `99 and |00 of the arms 91 Yand 98 and the upper jaws |03 and |04 engage the upper part of the axle andare'tightened thereon by the set screws |08 and |09 in the clevisesfl`06 and |01 in a posi- Ationsho'wn in Fig. -2,"so that' the grinding wheel 42 willl engage one of'theblades' Il I4. The frame I9 is adjusted vvithrespectio the platform by loosening the bo1t'32`s`o'that the grinding wheel will contact the blades of Athemower at substan- `tially'the right position,A the adjustability of the "the blades |4 is providedV by a gauge member |22 adaptedto ngage'over the tubular member 16 adjacent-the'motr 4|. The gauge |22 consists of an arm |23 secured" to the arm IV52 adjacent the Vheadtherof'by 'a`b0lt' |24. The arm |22 comprises'a' frame having a short arm |25 and a cross member' |26, the cross member being centrally and threadedlybored as at |26', and adapted to're'ceive ath'readed shank`|21 of a pin having a head" |28. The inner Vend of the threaded pin |21 is rotatably secured to a guide member |30 being notched at its end, as indicated at Isl, to slidably engage the respective arms |23 and |25 of the gauge, the guide member |39 being 'bored to receive the annular grooved end |32 of the pin which is held in the bore opening by pin |33. The opposite side of the guide is provided with a recess |36 in which is mounted, by pin or the like, a roller |31 adapted to engage against the tubular member 16 mounted on the outer end of the arms 35 and 36 of the frame. To keep the pin |21 from turning under vibration, a guide member |38 being centrally bored and provided with threads and having its ends slotted for sliding engagement on the arms |23 and |25, is located adjacent the end |26 and a compression spring |39 is provided therebetween urging the guide |33 away from the cross member |25, thus holding the threads of pin |21 under tension and preventing it from turning inadvertently. The arm |22 is pivotally mounted by the bolt |24 to the arm 52 for operation of the threaded pin |21 to exert downward pressure on the tubular member 16 which will raise the head 5d on the outer end of the arm 52 thereby raising the grinding wheel d2 to adjust the same with respect to the blades ||f| of the mower. The turning of the pin |21 in the opposite direction or in anti-clockwise direction will cause the arm to be lowered, thus lowering the grinding wheel it with respect to the blade Ill.

For sharpening of the stationary blade I5 is a frame Id@ comprising spaced arms Mil and |512 provided with openings near the respective ends adapted to receive the ends of rod |53 and ldd, the ends of the rod Het providing trunnions upon which the arms |-Ll| and |62 are mounted. The rod ldd is clamped by the jaws 91 and 93 and |ii3 and iild respectively and held securely therein by tightening of the screws |98 and |99 in the clevises itl@ and ll. Slots and |46 are prom vided in the respective ends of the arms |fl| and |532 and set screws M1 and m8 and adapted to engage the threaded lateral openings in the ends of the arms ld! and H52 for retaining the rods ldd and Had therein. The plate |5l which engages over the top of the rod IM is tack welded thereto. A pair of clamping members |5| and 152 is p-rovided for holding the blade |45 on the plate S59, the clamping members having flanges |53 depending from outer edges thereof and provided with threaded bores |54 adapted to receive the threaded ends |55 of locking pins |56 having heads il. The opposite ends of the clamping members are provided with inwardly extending flanges adapted to engage the underneath side of the plate |53 as indicated at |59 (Fig. 2l. Tightening of the locking pin on the plate |53 will hold the clamping member in the desired place to accommodate the stationary blade of different lengths.

In order to mount the stationary blade for sharpening on the framework structure each of the clamping members l! and |52 is provided with a web |89, and attached by welding or other suitable means to the outer side of the web is a tubular member |G| in which extends a pin ld having its upper end turned to form a hook |53, the other end being threaded to accommodate a thumb nut |653 for holding the blade H5 on the frame work structure.

In order to provide rotation of the frame |S on the platform 1 a bracket |61 is pivotally mounted to the forward side |68 of the channel member 39 with its lower end extending below the plate 2S and engages against a set screw |13 providing a stop for the frame |9 with respect to the platform. When it is desired to rotate the frame the bracket is turned so that its fore end will rise above the stop so that the device may be rotated. The frame |9 may be turned to 180 degrees and stopped by a set screw |1| is provided on the plate 20. The set screws |10 and |1| extend through threaded openings in pins |12 and |13 respectively and their inner ends will engage against the lower end of the bracket |61 to lock the bracket in place and also to provide proper alignment of the frame with the grinding wheel 42.

In operation of a device constructed and assembled as described, the axle of the mower is mounted in the clamping devices 92 and 93 and the frame |9 is slidably adjusted on the platform 1 so that the grinding wheel 42 carried on the frame is substantially in alignment with one of the blades ||4 on the reel of the mower.

The arms 35 and 36 have slots in their lower ends intersecting the openings in which the trunnions engage for mounting of the arms having downwardly extending jaws. One of the said jaws is provided with a threaded bore and the other a bore through which a cap screw 31 extends and engages in the threaded bore opening for clamping the arms on the trunnions. After the frame is adjusted on the platform, the cap screws 31 are loosened so that the arms may be adjusted to raise or lower the grinding wheel with respect to the blade, and then the cap screws are tightened.

The motor with its grinding wheel arm is then moved laterally so that the grinding wheel 42 is substantially adjacent one end of the blade, then the gauge |22 is adjusted for movement of the grinding wheel relative to the frame structure in order that the grinding wheel may contact said end of the blade. The upper ends of the arms 35 and 36 are slotted as at 12 and provided with cap screws 13' to form a movable friction grip, to provide for movement of the short shafts 13 in said arms withoutreadjustment of the threaded pins 99. Further adjustment of the grinding wheel to the blade may be accomplished by manipulation of the pin 99 to provide the proper alignment of the tubular member 16 with respect to the axis of the reel of the mower. The grinding wheel is then moved across to the opposite end of the blade and the pin 99 in that end of the eccentric mechanism adjusted to provide a more accurate alignment of the grinding wheel with respect to the blade.

In some instances, it may be desirable to provide for a higher grinding of the center of the blade than the respective ends. In order to accomplish this type of grinding, the set screw 88 is adjusted in the threaded bore B1 in the tubular member 16 in order to provide a bend or slight arc in the member 16 which guides movement of the grinding wheel with respect to the blade of the reel as it moves thereacross, the set screw 88 bearing against the rod 18 to accomplish this purpose.

After the proper adjustments have been made as above described, the grinding wheel is moved across the blade by a manual movement, the guide member ||9 with its shoulder |2| engaging the blade. As the wheel is moved thereacross'the reel will be turned so that the blade will be in alignment with the wheel at all times. The rotation of the grinding wheel in an anti-clockwise direction (Fig. 2) will exert a slight pressure against the blade to hold the blade in contact with the shoulder of the guide member. If fur 7 ther sharpening or each blade` is necessary. fil?? threaded pin |21 maybe turned by handle |28- to lower the. grinding wheel with respect to the blade to accomplish further cutting ofA the blade.

Some mowers may include certain obstructions and in order to accommodate for such exigepcies, I have provided a cutout portion |14- in the engl 9 and side of the platform, as illustrated in Figs. 1 and 2.

When it is desired to sharpen the stationary blade ||5, it is removed from the frame or the mower and fastened on the clamping members |,5,| and |52 by placing it on the Webs lli()r` and engaging the upper portion of the end thereof by hooks |63. The nuts |64 are tightenedV to holdthe blade securely in place. 'lghe bolt 3 2 ofthe trame is then loosened and the bracketk 6 7 is rotated to disengagement from. the. sten member so that; the frame |,9 may be rotated upon the pllilirm 1 to 180, or so that the grinding wheel will be adjacent to the stationary blade, The bracket isgthen rotated so that it is lowered and will engage against the set screw |1|`. rlhe frame i9 isthen adjusted on the platform to proper alignment of the grinding wheel with the cutting edge of the blade and the same adjustments made of the arms 35 and 36, gauge member |22 and eccentric mechanism as above described.

It will be obvious from the foregoing that I have provided an improved grinding machine for the blades of lawn mowersand which has novel clamping means for holding the mower` on the device and for adjustment of the grinding wheel at various positions with respect to theblades without removing the reeLf-rom themower, and also for sharpening of the stationary blade ofthe mower by rotation of theframeand its cutting wheel with respect to the platform supporting member.

What I claim and desire to secure by L etters .ci

carriage movable along the` guide rail, an arm projecting from themotor carriage` for supporting a motor driven toolabove one ofthe work supports, a complementary guide` rail carriedby the frame in spaced parallell relation with therst named guide rail, a gauge member movable along the complementary guide rail and having connection with said arm whereby the complementary guide rail cooperates with the rst namedvguide rail in supporting the grinding .wheel relatively to said work support, and meansrotatablymountl ing said frame on the carrier for turning the frame on said carrier` to, position the grinding wheel over the other of said worlf; supports.

2. A machine of the character described including a support, a substantially horizontal platform on the upper end otthe support, a Work: support on the platform, a. frame :having adjustable support on the platform and including laterally spaced braclgets, a .guiderail-Ihaving ends Carried by the. breliets, .e1-,tubular rail member, eccentrics supporting ends `ofthe tubular rail member on the brackets,- a-rod extendingV coaxially within the tubular rail member andV havingends connecting the` eccentrics, a setsereW-,cerried bythe .tubulerfreil-.member and having its inner end bearing upon the rod to curve the tubular rail member, a carriage having movable support on the guide rail and the tubular rail member, and a tool supported by the carriage for movement over the Work support.

3. A machine of the character described including a support, a substantially horizontal platform on the upper end of the support, a work support on the platform, a frame having adjustable support on the platform and including laterally spaced brackets, a guide rail having ends carried by thel brackets, a tubular rail member, eccentric supportingv endsl of the tubular rail member on the brackets, a rod extending coaxially within the tubular rail member and having ends connecting the eccentrics, a setscrew carried by the tubular rail member and having its inner end bearing upon the rod to curve the tubular rail member, a carriage having movable support on the guidel rail, a tool carrying arm on the carriage, and a gauge member having rolling support on the tubular rail member and having connection with the arm to support said tool over the Work support.

4. A machine of the character described including an upright support, a substantially horizontal platform cn the upper end of the support, spaced guides extending across the platform, a carrier movable along the guides, work supports on the platform at opposite ends of the guides, a frame, a guide rail carried by the frame transversely of the guides on the platform, a motor carriage movable along the guide rail, an arm projecting from the motor carriage, a grindinCr wheel on said arm, a tubular guide member carried by the frame in spaced parallel relation with the guide rail, a rod coaxially supported in the tubular guide member, a set screw carried by the tubular guide member and having bearing contact on the rod to effect curving of the tubular guide member, a gauge member movable along the tubular guide member and having connection with said arm whereby the tubular guide member cooperates with the guide rail in supporting the grinding wheel relatively to said work support, and means rotatably mounting the said frame on the carrier for turning the frame on said carrier to position the grinding wheel over the other of said work supports.

OSCAR C. RINK.

CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 348,753 Le Roy Sept. 7, 188i:` 1,389,588 Klay Sept. 6, 1921 1,409,641 Anderson Mar. 14, 1922 1,541,370 Medholdt June 9, 1925 2,149,774 Ingleman Mar. 7, 1939 2,180,911 Rogers Nov. 21, 1939 2,187,289 Utterback Jan. 16, 1940 2,279,798 Shelburne Apr. 14, 1942 2,281,055 Smith Apr. 28, 1942 2,286,970 Maynard June 16, 1942 2,377,126 Brown May 29, 1945 2,418,737 rIalboys Apr. 8, 1947 2,418,738 Talboys Apr. 8, 1947 2,432,851 Anderson Dec. 16, 1947 2,493,619 Comstock Jan. 3, 1950 2,562,578 Rickman July 31, 1951 

